#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;

int main()
{
	string s1 = "hello world";

	//cout << s1[0] << endl;
	//cout << s1[2] << endl;
	//cout << s1[4] << endl;

	s1[0] = 'x';
	s1[1] = 'x';
	s1[2] = 'x';
	cout << s1 << endl;

	return 0;
}